"Double metronome" for Etude op.10 no.12

It may be good only initially but....towards the execution, at speed, the micro-movements are certainly different. Therefore, I recommend (as already mentioned in other posts that I invite you to look for) studying with a certain speed and with a pause on every unit of time (in this case every half, assuming the time is in two), both by repeating the arrival and departure note, and without repeating the arrival note. Visually, it will be observed that in rapid movements, the hand makes different movements than in slow ones, and you will truly hear what the hands produce at speed. This way, the correct execution can be achieved in a short time. (This method was strongly suggested by F. Bajardi, the last pupil of Liszt and Teacher of my teacher)

I also use slower speeds but, as Paolo says, the micro-movements change. So I do it AFTER, when my brain has learned at least summarily where one needs to arrive and which gestures are to be adopted (this often happens unconsciously). Only then can slowness, even extreme slowness, become our magnifying glass and speed is not seen or perceived as an obstacle. Regarding the metronome for various pieces, it is true that it was often indicated by the composer, but this cannot be an imperative since there are aspects to take into account, including different mechanics and the different sensitivity and expressivity associated with the speeds peculiar to each pianist. Personally, I also adapt speeds based on the tuning of the instrument in front of me (for example, a "noisier" one makes the performance seem more animated).